A heat engine employing 3.5 g of helium gas is initially at STP. The gas goes through the following closed cycle:
i) Isothermal compression till the volume is halved.
ii) Isobaric expansion till the volume is restored to the initial value.
iii) Isochoric cooling till the pressure is restored to the initial value.
A) Determine how much work does the engine do per cycle?
B) Find out the thermal efficiency?